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We strengthen and put in a broader perspective previous results of the first two authors on colliding permutations. The key to the present approach is a new non-asymptotic invariant for graphs.

Combinatorics · Mathematics 2007-09-28 János Körner , Claudia Malvenuto , Gábor Simonyi

This article lays the foundations for an analogue of geometric group theory that studies actions on graphs by right quasigroups, including racks and quandles. We study markings of graphs that realize racks, and we introduce (di)graph…

Geometric Topology · Mathematics 2026-04-01 Luc Ta

An extension of an induced path $P$ in a graph $G$ is an induced path $P'$ such that deleting the endpoints of $P'$ results in $P$. An induced path in a graph is said to be avoidable if each of its extensions is contained in an induced…

Combinatorics · Mathematics 2021-10-22 Vladimir Gurvich , Matjaž Krnc , Martin Milanič , Mikhail Vyalyi

We show that every locally sparse graph contains a linearly sized expanding subgraph. For constants $c_1>c_2>1$, $0<\alpha<1$, a graph $G$ on $n$ vertices is called a $(c_1,c_2,\alpha)$-graph if it has at least $c_1n$ edges, but every…

Combinatorics · Mathematics 2017-05-04 Michael Krivelevich

Suppose G is a nilpotent, finite group. We show that if {a,b} is any 2-element generating set of G, then the corresponding Cayley digraph Cay(G;a,b) has a hamiltonian path. This implies there is a hamiltonian path in every connected Cayley…

Combinatorics · Mathematics 2011-07-04 Dave Witte Morris

The cutoff phenomenon describes a sharp transition in the convergence of an ergodic finite Markov chain to equilibrium. Of particular interest is understanding this convergence for the simple random walk on a bounded-degree expander graph.…

Probability · Mathematics 2010-03-19 Eyal Lubetzky , Allan Sly

In this paper we develop a framework to study observability for uniform hypergraphs. Hypergraphs, being extensions of graphs, allow edges to connect multiple nodes and unambiguously represent multi-way relationships which are ubiquitous in…

Dynamical Systems · Mathematics 2023-09-19 Joshua Pickard , Amit Surana , Anthony Bloch , Indika Rajapakse

We provide a criterion to distinguish two graphs which are indistinguishable by $2$-dimensional Weisfeiler-Lehman algorithm for almost all graphs. Haemers conjectured that almost all graphs are identified by their spectrum. Our approach…

Combinatorics · Mathematics 2025-11-21 Wei Wang , Da Zhao

Witte Morris showed in [21] that every connected Cayley graph of a finite (generalized) dihedral group has a Hamiltonian path. The infinite dihedral group is defined as the free product with amalgamation $\mathbb Z_2 \ast \mathbb Z_2$. We…

Combinatorics · Mathematics 2026-01-16 Babak Miraftab , Konstantinos Stavropoulos

Both the path integral measure in field theory and ensembles of neural networks describe distributions over functions. When the central limit theorem can be applied in the infinite-width (infinite-$N$) limit, the ensemble of networks…

High Energy Physics - Theory · Physics 2023-12-15 Mehmet Demirtas , James Halverson , Anindita Maiti , Matthew D. Schwartz , Keegan Stoner

We obtain an effective enumeration of the family of finitely generated groups admitting a faithful, properly discontinuous action on some 2-manifold contained in the sphere. This is achieved by introducing a type of group presentation…

Combinatorics · Mathematics 2019-01-04 Agelos Georgakopoulos , Matthias Hamann

Motivated by the Cauchy-Davenport theorem for sumsets, and its interpretation in terms of Cayley graphs, we prove the following main result : There is a universal constant e > 0 such that, if G is a connected, regular graph on n vertices,…

Combinatorics · Mathematics 2009-10-25 Peter Hegarty

The well-known characterization of two-ended groups says that every two-ended group can be split over finite subgroups which means it is isomorphic to either by a free product with amalgamation $A\ast_C B$ or an HNN-extension $\ast_{\phi}…

Combinatorics · Mathematics 2018-12-13 Babak Miraftab , Tim Rühmann

In this paper, we derive the large deviations principle for the Potts model on the complete bipartite graph $K_{n,n}$ as $n$ increases to infinity. Next, for the Potts model on $K_{n,n}$, we provide an extension of the method of aggregate…

Probability · Mathematics 2017-04-05 Jose C. Hernandez , Yevgeniy Kovchegov , Peter T. Otto

A finite dimensional operator that commutes with some symmetry group admits quotient operators, which are determined by the choice of associated representation. Taking the quotient isolates the part of the spectrum supporting the chosen…

Mathematical Physics · Physics 2023-11-30 Ram Band , Gregory Berkolaiko , Christopher H. Joyner , Wen Liu

We say that a $d$-regular graph is a $\gamma$-expander if for every not too large set of vertices $S$, there are at least $\gamma d |S|$ edges leaving $S$, and we say that a graph $G$ is $\gamma$-far from bipartite if at least $\gamma e(G)$…

Combinatorics · Mathematics 2026-05-15 Domagoj Bradač , Oliver Janzer

We classify the countable ultrahomogeneous 2-vertex-colored graphs in which the color classes are imprimitive, i.e., up to complementation they form disjoint unions of cliques. This generalizes work by Jenkinson, Lockett and Truss as well…

Combinatorics · Mathematics 2023-06-16 Sofia Brenner , Irene Heinrich

We extend the concept of graph isomorphisms to multilayer networks with any number of "aspects" (i.e., types of layering). In developing this generalization, we identify multiple types of isomorphisms. For example, in multilayer networks…

Physics and Society · Physics 2017-02-17 Mikko Kivelä , Mason A. Porter

We investigate the graph isomorphism (GI) in some cospectral networks. Two graph are isomorphic when they are related to each other by a relabeling of the graph vertices. We want to investigate the GI in two scalable (n + 2)-regular graphs…

Quantum Physics · Physics 2014-12-04 M. A. Jafarizadeh , F. Eghbalifam , S. Nami

We present the theory of multifunctions applied to graphs. Its interesting feature is that walks are recognized as iterations. We consider the graphs with arbitrary number of vertices which are determined by multifunctions. The mutually…

General Mathematics · Mathematics 2017-11-02 Artur Gizycki